- Bought a $2.58 HDMI-to-VGA DAC for Nintendo Switch to CRT, but audio out had severe noise and distortion issues.
- Diagnosed problems including impedance, delta-sigma DAC switching noise, and missing filtering capacitors on the PCB.
- Built a lowpass filter with resistor and capacitor; discovered DAC internal resistance ~600 ohms, making filter ineffective.
- Recalculated filter using internal resistance; optimal capacitor is ~5.1 nF for 50 kHz cutoff; used series 10 nF caps as bodge.